In the operation of oil bath lip seals on tractor truck and tractor trailer axles, the sealing lips usually bear on an axle ring instead of directly on a portion of the axle or spindle. With such an arrangement, if excessive wear occurs, the axle ring may be replaced instead of rebuilding or replacing the whole axle. In this type of arrangement, the axle ring is normally sized to form a press fit on the axle or spindle. Thus, on a typical spindle with a diameter between 4.768 and 4.762 inches, the original I.D. of the axle ring would be in the range of 4.758 to 4.753 inches.
At present, when wear occurs to the extent that replacement of the axle ring is necessary, the worn ring is customarily peened with a ball peen hammer or with a hammer and a dull chisel or the like. The peening action stretches a portion of the axle ring until it slips easily off of the axle. However, this process does have some drawbacks. The spindle can be damaged if the peening action is too forceful or if the spindle is hit directly by the peen. Another major problem is that the axle ring is frequently inaccessible for conventional peening. Brake shoes, cylinders, backing plates or other parts mounted on or close to the axle in many cases make conventional peening impractical, if not impossible. In these situations and even though there is significant risk of damage to axles, axle rings are usually removed by cutting with a hammer and chisel or by prying with a special pry bar. Otherwise a major disassembly is required to gain access for peening. All of these alternatives are time consuming and costly.